Dolphin Species Goes Extinct Due to Humans Dolphin Species Goes Extinct Due to Humans By Charles Q. Choi, Live Science Contributor | August 8, 2007 12:52pm ET MORE The Yangtze River dolphin (Lipotes vexillifer), or baiji, are a type of freshwater dolphin thought to be the first dolphin species driven to extinction due to the impact of humans. The above male Yangtze River dolphin, named "Qi Qi," was held at the Wuhan dolphinarium from 1980 to 2002. Credit: Ding Wang et al. | Biology Letters The Yangtze River dolphin is now almost certainly extinct, making it the first dolphin that humans drove to extinction, scientists have now concluded after an intense search for the endangered species. The loss also represents the first global extinction of megafauna—any creature larger than about 200 pounds (100 kilograms)—for more than 50 years, since the disappearance of the Caribbean monk seal (Monachus tropicalis).

The Yangtze River dolphin or baiji (Lipotes vexillifer) of China has long been recognized as one of the world's most rare and threatened mammal species. "It's a relic species, more than 20 million years old, that persisted through the most amazing kinds of changes in the planet," said marine biologist Barbara Taylor at the National Oceanic and Atmospheric Administration's Fisheries Service. "It's been here longer than the Andes Mountains have been on Earth." In 1999, the surviving baiji population was estimated to be as low as just 13 dolphins, compared to 400 known baiji in 1981. The last confirmed glimpse of a baiji was documented by a photo taken in 2002, although unverified sightings were reported as recently as 2006. An international team of scientists conducted an intense six-week search for the dolphin in two research vessels during November and December 2006, covering the entire known range of the baiji in the 1,037-mile (1,669-kilometer) main channel of the Yangtze River.

The researchers and their instruments failed to see or hear any evidence that the dolphin survives. "It was a surprise to everyone on the expedition that we didn't have any sightings at all, that the extinction just happened so quickly," Taylor recalled. This would make the baiji the first cetacean—that is, dolphin, porpoise or whale—to go extinct because of humans . The species was probably driven to extinction by harmful fishing practices that were not even devised to harm the dolphins, such as the use of gill nets, rolling hooks or electrical stunning. The findings are detailed Aug. 7 in the journal Biology Letters. "In the past, you had this out-of-control whaling that still didn't result in any extinctions, but these accidental deaths, which are much less visible to people, are much more insidious," Taylor said. Even if any baiji exist that scientists did not find, the continued deterioration of the Yangtze region's ecosystem—home to roughly 10 percent of the world's human population—means the species has no hope of even short-term survival as a viable population, the researchers added.

"To help save the endangered Yangtze finless porpoises (Neophocaena phocaenoides asiaeorientalis) that also live in the river, we'll likely have to keep them in lake preserves or raise them in captivity, because the situation in that river doesn't look like it can be controlled at this point," Taylor explained. With the loss of the Yangtze River dolphin, the world's most critically endangered cetacean species now is the vaquita or Gulf of California porpoise (Phocoena sinus), of which 250 survive. The vaquita and other coastal dolphins around the world now face the same peril that claimed the baiji—accidental deaths from fishing. "We have to find a way to let small-time fishermen put food on their tables that doesn't involve putting gill nets in the water that decimate these species ," Taylor said.

"Unless we figure out a way to deal with this problem, the baiji may be the first in quite a long line of animals to face extinction." IMAGE GALLERY: Endangered and Threatened Wildlife List of Mammals Extinct after 1500 AD | RoboConsumer List of Mammals Extinct after 1500 AD September 23, 2007 in Environment The table below shows the complete list of mammal species classed as extinct since 1500 AD (the past 500 years). Subspecies are included at the end of the table. The data comes from the 2008 Red List of threatened species maintained by the World Conservation Union — also known as the International Union for the Conservation of Nature (IUCN). It’s possible that other mammal species became extinct during that period without their disappearance having been recorded. The rate of extinction for all animals has increased in recent centuries. There are 247 Critically Endangered mammals in the 2008 database — 188 mammal species and 59 subspecies. Just one example is the Baiji dolphin, or Yangtze river dolphin (Lipotes vexillifer).

The database entry states: “The preponderance of evidence indicates that the baiji is very close to extinction or may already be extinct.” Critically Endangered species of any taxonomic group can be tagged as “Possibly Extinct” or “Possibly Extinct in the Wild.” Click on the scientific names to go to the database entries for the species. Mammals Extinct after 1500 AD # China's Rare River Dolphin Now Extinct, Experts Announc China's Rare River Dolphin Now Extinct, Experts Announc Stefan Lovgren for National Geographic News December 14, 2006 The rare Chinese river dolphin has gone extinct, according to scientists who could not find a single one of the animals during a six-week search on China 's Yangtze River.

The small, nearly blind white dolphin, also known as the baiji, was nicknamed "the goddess of the Yangtze." (See China map ) "If there are any baiji left in the river, they won't have any chance of survival." If Pfluger's team is correct, the baiji will be the first large aquatic mammal to have gone extinct since hunting and overfishing killed off the Caribbean monk seal in the 1950s. Yangtze Dams, Ship Traffic to Blame? The delicate dolphin, which dates back 20 million years, was found only in China's longest river, the Yangtze. Using high-tech optical instruments and underwater microphones on two research vessels, the international team of 30 scientists and crew scoured almost 2,175 miles (3,500 kilometers) of the river, from Yichang near the Three Gorges Dam to Shanghai, for any signs of the dolphin. "When we started, we were really optimistic about finding them, but as each day went by it became increasingly clear that there are no baiji left," Pfluger said.

The dolphin's population had plummeted from about 400 in the late 1980s to less than 100 in the mid-1990s. The last search for the animal, in 1997, yielded 13 sightings. One fisher claimed to have seen a baiji in September 2004. The Baiji Dolphin: The Functionally Extinct Species of China's Yangtze River The Baiji Dolphin: The Functionally Extinct Species of China's Yangtze River The Baiji Dolphin: The Functionally Extinct Species of China’s Yangtze River ADVERTISEMENT Photo: Stephen Leatherwood The Baiji river dolphin has a tragic history. This beautiful water mammal once swam in China’s Yangtze River, thousands of them playing, fishing and diving. Yet while in the 1950s there were approximately 6,000 animals, the last possible sighting was in 2007. It will be the first well-studied whale, dolphin or porpoise species to have become extinct due to the actions of man.

It seems that a rare animal – technically listed as critically endangered, partially because of the one unverified sighting – has been wiped from the face of the planet. Photo: Stephen Leatherwood Chinese legend has it that the dolphins are the reincarnation of a drowned princess, but during China’s “Great Leap Forward” – when the government tried to force the change from an agrarian and rural economy to an industrialized one – officials denounced the esteem it was held in and it was hunted for food and skin. It also lived in the Yangtze River, one of the world’s most degraded, polluted and busiest waterways, causing extra pressure on it from boats and pollution. Photo: Stephen Leatherwood Three major man-made threats were specific, though. In the 70s and 80s, half of the river dolphin deaths were due to entanglement in fishing nets and lines. In the early part of the 21st century electric fishing had become the most immediate threat, and then the Three Gorges Dam was built and completed in 2006, further destroying the dolphins’ habitat while increasing shipping.

Conservationists went to study the dolphins, hoping to use an oxbow off the river as a breeding place in which the remaining dolphins might safely give birth, but to their utter despair, not one dolphin could be found. It behooves us to heed the lesson from this tragedy and start considering our impact on precious species before we start altering the landscape and destroying habitats. Perhaps the Baiji river dolphins could have been saved if thought was given to how to minimize our impact or at least provide a safe haven for breeding in advance. Waiting until after the numbers had started to drastically decline seems to have sealed the dolphins’ fate. The EDGE of Existence says more studies need to be done to take the lessons from the Baiji and apply them to all the other river dolphins in the world that are at risk. In fact, some governments may not realize the true extent of the threat. Dolphin that just became extinct! - SRB2 Message Board Dolphin that just became extinct! User Name View Poll Results: How does this extinction make you feel? upset Voters: 13. You may not vote on this poll Dolphin that just became extinct!

Read this article from wikipedia: The Baiji (Traditional Chinese: 白鱀豚; pinyin: bï¿½ijï¿½tï¿½n) (Lipotes vexillifer, Lipotes meaning "left behind", vexillifer "flag bearer") was a freshwater dolphin found only in the Yangtze River in China. Nicknamed "Goddess of the Yangtze" (長江女神) in China, the dolphin was also called Chinese River Dolphin, Yangtze River Dolphin, Beiji, Pai-chi (Wade-Giles), Whitefin Dolphin and Yangtze Dolphin. It is not to be confused with the Chinese White Dolphin (中華白海豚). Efforts were made to conserve the Baiji after its population began a drastic decline in recent decades. The odds were against the mammal, however, and a late 2006 expedition failed to find any in the river. Organizers declared the Baiji "functionally extinct",[1] making it the first aquatic mammal species to become extinct since the 1950s.

Causes of decline The World Conservation Union (IUCN) has noted the following as threats to the species: a period of hunting by humans during the Great Leap Forward, entanglement in fishing gear, the illegal practice of electric fishing, collisions with boats and ships, habitat loss, and pollution. During the Great Leap Forward, when traditional veneration of the Baiji was denounced, it was hunted for its flesh and skin, and quickly became scarce. As China developed economically, pressure on the river dolphin grew significantly. Industrial and residential waste flowed into the Yangtze. The riverbed was dredged and reinforced with concrete in many locations. Ship traffic multiplied, boats grew in size, and fishermen employed wider and more lethal nets. Noise pollution caused the nearly blind animal to collide with propellers. Stocks of the dolphin's prey declined drastically in recent decades as well, with some fish populations declining to one thousandth of their pre-industrial levels. In the 1970s and 1980s, an estimated half of Baiji deaths were attributed to entanglement in fishing gear.

By the early 2000s, electric fishing was considered "the most important and immediate direct threat to the Baiji's survival."[10] Though outlawed, the destructive fishing technique is widely practiced throughout China. The building of the Three Gorges Dam further reduced the dolphin's habitat and facilitated an increase in ship traffic.

Timeline circa 3rd century BC: population estimated at 5,000 animals 1950s: population was estimated at 6,000 animals 1958-1962: The Great Leap Forward denounces the animal's traditional venerated status 1979: The People's Republic of China declares the Chinese River Dolphin endangered 1983: National law declares hunting the Chinese River Dolphin illegal 1984: The plight of the Baiji draws headlines in China[12] 1986: Population estimated to be 300 1989: Gezhouba Dam complete 1990: Population estimated to be 200 1994: Construction of the Three Gorges Dam begins 1996: IUCN lists the species as critically endangered 1997: Population estimated to be less than 50 (23 found in survey); a dead baiji was found with 103 separate open wounds[2] 1998: 7 found in survey 2003: Three Gorges Dam begins filling reservoir 2004: Last known sighting, a

 stranded dead dolphin 2006: None found in survey, declared "with all probability extinct" Current status Main article: Yangtze Freshwater Dolphin Expedition 2006 The Xinhua News Agency announced on 4 December 2006 that no Chinese River Dolphins were detected in a six-week survey of the Yangtze River conducted by 30 researchers.

The failure of the Yangtze Freshwater Dolphin Expedition (长江淡水豚类考察) raised suspicions of the first unequivocal extinction of a cetacean species due to human action[26] (some extinct baleen whale populations might not have been distinct species). Poor water and weather conditions may have prevented sightings,[1] but expedition leaders declared it "functionally extinct" on 13 December 2006 as fewer are likely to be alive than are needed to propagate the species. No aquatic mammal has become extinct since the Caribbean Monk Seal disappeared in the 1950s. Several land-based mammal species and subspecies have become extinct in recent decades. Some scientists retain hope for the species. Wang Limin, director of the World Wildlife Fund Wuhan office said, "The fact that the expedition didn't see any Baiji dolphins during this expedition does not necessarily mean that the species is extinct or even 'effectively extinct', because it covered a considerable distance in a relatively short period of time... However, we are extremely concerned.

The Yangtze is highly degraded, and we spotted dramatically fewer Finless Porpoises than we have in the past."[ This is shocking for the people who love animals espescially dolphin lovers. How does this extinction affect you? Edit: Here is a picture of a baiji: Edit #2: Here is a picture of the Baiji's cousin the finless porpoise: Aren't they just adorable? *Note* these pictures aren't mine. __________________ Baiji dolphin | 10 animals presumed extinct in the last decade | MNN - Mother Nature Network 10 animals presumed extinct in the last decade By: Laura Moss on Oct. 10, 2016, 10:56 a.m. (Photo: ZUMA Press) Baiji dolphin China's baiji dolphin , or Yangtze River dolphin, is listed as critically endangered, but scientists say it may already be extinct. In 2006, scientists from the Baiji Foundation traveled up the Yangtze River for more than 2,000 miles equipped with optical instruments and underwater microphones, but were unable to detect any surviving dolphins.

The foundation published a report on the expedition and declared the animal functionally extinct, meaning too few potential breeding pairs remained to ensure the species' survival. The last documented sighting was in 2002, but in October 2016, a team of amateur conservationists claimed to have seen the creature near the city of Wuhu in China's Anhui province. “No other creature could jump out of the Yangtze like that,” team leader Song Qi told the Chinese website Sixth Tone . “All the eyewitnesses — which include fishermen — felt certain that it was a baiji.” However, the team wasn't able to photograph the dolphin and had no other conclusive proof of its existence. Plus, none of the people who witnessed the sighting were experts on the animal. The decline in the baiji dolphin population is attributed to a variety of factors including overfishing, boat traffic, habitat loss, pollution and poaching. Deemed "the goddess of the river," the dolphin's skin was highly valuable and used to make gloves and handbags.

CMS: Lipotes vexillifer, baiji English: Yangtse river-dolphin; baiji; whitefin dolphin German: Chinesischer Flussdelphin Spanish: Baiji; Delfín de China French: Baiji; Dauphin de Chine Family Lipotidae Lipotes vexillifer © Würtz-Artescienza (see " links ") 1. Description The baiji has been the rarest and most endangered cetacean in the world (Smith et al. 2008); it is currently thought to probably be extinct (IUCN, 2009). It was a very graceful animal, with a very long, narrow and slightly upturned beak. The baiji could easily be identified by the rounded melon, longitudinally oval blowhole, very small eyes, low triangular dorsal fin and broad, rounded flippers. The coloration was bluish-grey to grey above and white to ashy-white below. Females were larger than males, reaching 253 cm as opposed to 229cm (Zhou, 2002). 2.

Distribution The baiji was an exclusively freshwater species and ranged in the lower and middle reaches of the Chang Jiang (Yangtze River), from its estuary upstream for 1,600 km as far as the gorges above Yichang (20m above sea level). At least one record was reported from the lower Fuchun Jiang at Tonglu (Rice, 1998). Individuals may have entered some tributary lakes during intense flooding (Zhou, 2002). Distribution of the possibly extinct Lipotes vexilifer in the Chang Jiang (Yangtse River) and its tributaries (Smith et al. 2008 © IUCN; enlarge map ). 3. Population size Zhou et al. (1998) report that boat surveys conducted along a 500km section of the Yangtze River between Zhenjiang and Hukou in 1989-1991 resulted in identification of seven individual baiji based on natural markings.

There were 7 sightings of baiji in May 1989, 4 sightings in March 1990 and 6 sightings in April-May 1990, resulting in an estimated population size of about 30 individuals in the 500-km river study area. If the baiji was still inhabiting its historical 1,600 km range in the Yangtse River, and population density was similar throughout this habitat section, there may have been 100 baiji left in the river at that time. However, results of subsequent surveys of almost all the species' previous range, Shanghai to Yichang, suggested that the population was very small and in further decline. In 1998 only a few dozen animals may have still been alive (Zhou, 2002). From observations between 1997-1999, Zhang et al. (2003) concluded that 13 individuals could be considered as a minimum number of the baiji in the Yangtse River at that time. The annual rate of population decrease was roughly estimated as 10%.

The distribution range of the baiji was less than 1,400 km in length in the Yangtze main river. Distances between the two nearest groups of baiji appeared to be increasing. In Dongting Lake and Boyang Lake, the baiji became extinct by 1999 (Yang et al. 2000). Finally, an intensive six-week multi-vessel visual and acoustic survey carried out in November-December 2006, covering the entire historical range of the baiji in the main Yangtze channel, failed to find any evidence that the species survives (Turvey et al. 2007). The authors concluded that the baiji is now likely to be extinct, probably due to unsustainable by-catch in local fisheries. This represents the first global extinction of a large vertebrate for over 50 years, only the fourth disappearance of an entire mammal family since AD 1500, and the first cetacean species to be driven to extinction by human activity. There are no baiji in either natural reserves or in dolphinariums (Smith et al. 2008). 4.

Biology and Behaviour Habitat: Baiji were generally found in eddy countercurrents below meanders and channel convergences. The Yangtze River is turbid, and visibility from the surface downward is about 25-35cm in April and 12cm in August. Baiji eyes were correspondingly reduced, much smaller than those of other dolphins and placed higher on the head. However, they were functional, and baiji could distinguish objects placed on the surface (Zhou, 2002). Zhang et al. (2003) reported that baiji showed a significant attraction to confluences and sand bars with large eddies. Schooling: They generally lived in small groups of 3-4 animals, largest observed group size being 16 animals (Zhou, 2002). Two typical sightings are described (Zhang et al. 2003), in which surfacing and movements of baiji were recorded. Baiji were often found swimming together with finless porpoises. In the surveys they occurred in the same group in 63% of occurrences. Behaviour: Baiji would surface without splashing and breathe smoothly.

Short breathing intervals of 10-30s alternated with a longer one of up to 200s (Zhou, 2002). Reproduction: The baiji probably bred and gave birth in the first half of the year. The peak calving season appeared to be February to April (Zhou, 2002). Food: Any available species of freshwater fish was taken, the only selection criterion appears to have been size (Zhou, 2002). 5. Migration Reyes (1991) classified the species as "non-migratory". Peixun (1989) reported movements within home ranges but not migratory behavior. However, baiji also made long-range movements. Hua et al. (1994) recorded a single individual moving more than 300 km from March 1989 to January 1992, implying that the baiji's distribution range may have been dynamic. Anecdotal information from fishermen in the river during the surveys indicated that baiji moved upstream when water rose in the spring and downstream when water receded in winter (Zhang et al. 2003).

Zhou et al. (1998) showed from photographic identifications and sighting records that baiji groups made both local and long-range movements. The largest recorded movement of a recognisable baiji was 200+ km from the initial sighting location. 6. Threats As summarized by Zhou (2002), the threats faced by the baiji included river traffic, fishing gear, reduction of fish stocks, and water pollution. Zhang et al. (2003) added to this list illegal electrical fishing, accounting for 40% of known mortality during the 1990s, and engineering explosions for maintaining navigation channels, which became another main cause of baiji deaths. Furthermore the Yangtze was suffering massive habitat degradation that likely added to the onset of the baiji's demise: - The banks of the river have been modified extensively to prevent destructive flooding of agricultural areas, thus reducing the floodplain area (Zhou, 2002). - Wastewater volume discharged into the Yangtze is about 15.6 billion cubic meters per year.

Approximately 80% of these wastewaters are discharged directly into the environment without treatment (Zhou, 2002). - Dudgeon (1995) reported that in the Zhujiang, dam construction has caused reductions in fisheries stocks but here, as elsewhere in China, the ecologically damaging consequences of river regulation are exacerbated by overfishing and increasing pollution of rivers by sewage, pesticides and industrial wastes. o In addition, deforestation and soil erosion in the Chang Jiang basin have given rise to siltation and degradation of floodplain habitats (Dudgeon, 1995). Finally, Rosel and Reeves (2000) pointed out another, equally threatening effect. These animals faced an additional suite of potentially serious problems that were often overlooked, perhaps because they were not so obvious. The genetic and demographic consequences associated with very small population size can result in extinction even when effective measures are in place to protect the animals and their habitat. Small populations tend to harbor less genetic variation than large populations. In addition, small populations are more strongly affected by processes of genetic drift and inbreeding, both of which can further reduce genetic variability.

Genetically depauperate populations may have lower fitness, a reduced ability to adapt to changes in their environment over time, and decreased evolutionary potential. Finally, small populations may also be more vulnerable to demographic stochasticity, which can accelerate the process of extinction. Awareness of the genetic and demographic consequences of small population size should be integral to planning for conservation of endangered river cetacean species and populations. 7. Remarks Range state (Smith et al. 2009): China Huan and Chen reported as early as 1992 that "the distribution density of baiji in the river section of Ouchikou-Chenglingji (158 kilometres) was gradually diminishing. Its distribution density in the section under research diminished from 3.67 km/per dolphin in 1986 to 10.36 km/per dolphin in 1991. The baiji has been listed as First-Class Animal under the protection of the Chinese Government, but its population size decreases further and human activities still severely endanger its existence. With further human exploitation of the Yangtse River, new key water-control projects will be built.

Hence, a conservation strategy must be adopted to rescue this species." The IUCN lists the species as "critically endangered and possibly extinct" (C2a(ii); D). It was a relict species and the only living representative of the family Lipotidae and met the definition of a Critically Endangered (CR) species, as it is facing an extremely high risk of extinction in the wild (Smith et al. 2008). L. vexilifer is listed in appendices I and II of CITES. Because it was not an internationally migrating species, it was not listed by CMS. 8. Sources · Dudgeon D (1995) River regulation in southern China: Ecological implications, conservation and environmental management. Regulated Rivers Research & Management 11(1): 35 - 54 · Hua Y, Gao S, Zhang J. 1994. Population size of baiji and the analysis of the population decreasing. In Working Paper on Baiji Population and Habitat Viability Assessment Workshop Report, Zhou K, Ellis S, Leatherwood S, Bruford M, Seal US (eds), 41-45.

· Huan Y, Chen P (1992) Investigation for impacts of changes of the lower reach of Gezhou Dam between Yichang and Chenglingji on the baiji, Lipotes vexillifer vexillifer after its key water control project founded. J Fish China Shuichan Xuebao. 16(4): 322-329 · Peixun (1989) Baiji - Lipotes vexilifer. In: Handbook of Marine Mammals (Ridgway SH, Harrison SR eds.) Vol. 4: River Dolphins and the Larger Toothed Whales. Academic Pres, London, pp. 25 - 44. · Reyes JC (1991) The conservation of small cetaceans: a review. Report prepared for the Secretariat of the Convention on the Conservation of Migratory Species of Wild Animals. UNEP / CMS Secretariat, Bonn. · Rice DW (1998) Marine mammals of the world: systematics and distribution. Society for Marine Mammalogy, Special Publication Number 4 (Wartzok D, Ed.), Lawrence, KS. USA.

· Rosel PE, Reeves RR (2000) Genetic and demographic considerations for the conservation of Asian river cetaceans. In: Reeves, RR (ed); Smith, BD (ed); Kasuya, T (ed). Biology and conservation of freshwater cetaceans in Asia. 23: 144-152 · Smith BD, Zhou K, Wang D, Reeves RR, Barlow J, Taylor BL, Pitman R (2008) Lipotes vexillifer. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.2. < · Turvey ST, Pitman RL, Taylor BL, Barlow J, Akamatsu T, Barrett LA, Zhao X, Reeves RR, Stewart BS, Wang K, Wei Z, Zhang X, Pusser LT, Richlen M, Brandon JR, Wang D (2007) First human-caused extinction of a cetacean species?

Biol Lett 3: 537-540 · Zhang, X, Jiang G, Jiang X, Li Y (2001) Impacts on baiji and finless porpoise by some projects of preventing and controlling flood in the Yangtze River, with conservation strategies. Resour Environ Yangtze Basin 10: 242-246 · Zhou K (2002) Baiji - Lipotes vexilifer. In: Encyclopedia of marine mammals (Perrin WF, Würsig B, Thewissen JGM, eds.) Academic Press, San Diego, 58 - 61. · Zhou K, Sun J, Gao A, Wuersig B. (1998) Baiji (Lipotes vexillifer) in the lower Yangtze River: Movements, numbers, threats and conservation needs. Aquatic.Mammals.

24(2):123-132 · Yang J, Xiao W, Kuang X-A, Wei Z, Liu R-J (2000) Studies on the distribution, population size and the active regularity of Lipotes vexillifer and Neophocaena phocaenoides in Dongting Lake and Boyang Lake. Resour Environ Yangtze Basin 9: 443-450 · Zhang X, Wang A, Liu R, Wei Z, Hua Y, Wang Y, Chen Z, Wang L (2003) TheYangtze River dolphin or baiji (Lipotes vexillifer): population status and conservation issues in theYangtze River, China. Aquatic Conserv: Mar. Freshw. Ecosyst. 13: 51-64 © Boris Culik (2010) Odontocetes. The toothed whales: "Lipotes vexillifer". UNEP/CMS Secretariat, Bonn, Germany. © Illustrations by Maurizio Würtz, Artescienza. © Maps by IUCN.

Chinese River Dolphin / Baiji <em>(Lipotes vexillifer) </em> :: NOAA Fisheries large variety of freshwater fish species Behavior: very little is known about the behavior, but they depend largely on underwater sound for orientation, feeding, and communication and, just like most dolphin species, they produce clicks and whistles The Chinese river dolphin is a freshwater dolphin and one of the most endangered animals on Earth. It is also known as the Yangtze river dolphin, baiji, white-flag dolphin, and white-fin dolphin. Nicknamed "Goddess of the Yangtze," it was regarded as the goddess of protection by local fishermen and boatmen in China (Zhou, 1991). The Yangtze river dolphin is pale blue to gray on the dorsal (back) side, white on the ventral (belly) side. It has a long and slightly-upturned beak with 31-36 conical teeth on either jaw. Its dorsal fin is low and triangular in shape, and resembles a light-colored flag when the dolphin swims just below the surface of the murky Yangtze River, hence the name "white-flag" dolphin. It has smaller eyes compared to oceanic dolphins.

A mature Yangtze river dolphin is about 8 feet (2.5 m) long and weighs about 500 pounds (220 kg). Though it has been described in classical Chinese literature and folklore as early as 200 B.C., the Yangtze river dolphin was not known to the western world until 1916, when Charles M. Hoy, the son of an American missionary, shot one while duck hunting on Dongting Lake, China (Zhou, 1991). Subsequently, this species was formally introduced to the scientific community by Gerrit S. Miller, Jr., a curator at the Smithsonian Institute's National Museum of Natural History. Just like the other species of river dolphins (the Amazon river dolphin, Inia geofrensis; the La Plata river dolphin, Pontoporia blainvllei; and the Indian river dolphin, Platanista gangetica), the Yangtze river dolphin originated from the ocean. The ancestor of the Yangtze river dolphin resided in the shallow sea that inundated the Yangtze River Basin during the globally high sea levels of the Middle Miocene period (approximately 20 million years ago).

After the subsequent sea-level lowering and transition to a freshwater river during the late Neogene period, the dolphins remained and evolved to become the present-day Yangtze river dolphins (Hamilton et al., 2001). The Yangtze river dolphin is thought to breed in the first half of the year, with the peak calving season between February and April. Gestation lasts 10-11 months, and a newborn calf measures about 3 feet (1 m). Dolphins reach sexual maturity at 4-6 years of age (Zhou, 2004). The life expectancy for the Yangtze river dolphin is about 25 years, based on an individual in captivity. Very little is known about the ecology, behavior, and acoustics of the Yangtze river dolphin. Groups of two to six animals were most commonly seen, although aggregations of up to 16 animals have also been observed (Zhou, 2004). The Yangtze river dolphin feeds on a large variety of freshwater fish species (Zhou, 2004).

These dolphins are generally shy of boats, and often expose only the top of the head, dorsal fin, and a small part of the back when surfacing (Zhou, 2004). Due to the poor visibility in the murky Yangtze River, the Yangtze river dolphin depends largely on underwater sound for orientation, feeding, and communication. Just like most dolphin species, the Yangtze river dolphin produces two types of sounds: clicks and whistles (Akamatsu et al., 1998; K. Wang et al., 2006a). Clicks are believed to be used primarily for navigation and identifying prey and other objects in the surrounding environment (Au, 1993). Whistles are frequency modulated (pitch changes with time) sounds and are thought to be used for communication. (K. Wang et al., 2006a Habitat The Yangtze river dolphin is found only in freshwater, specifically in the Yangtze River in China. Distribution Historically, the species occurred in the middle to lower reaches of the Yangtze River, along with its tributaries and connecting lakes in China (Zhou et al., 1977).

Due to habitat loss caused by rapid development along the Yangtze River, its distribution was largely reduced. More recently, it is believed that the Yangtze river dolphin is limited to the main channel of an 870-mile (1,400-km) river section between Jingzhou and Jiangyin (Zhang et al., 2003). Population Trends No historical population estimate of the Yangtze river dolphin is available. However, the population of the Yangtze river dolphin has declined drastically and rapidly since the 1950s (Zhou et al., 2004; Turvey et al., 2007). The estimated population size declined to 400 by the 1980s (Zhou et al., 1982). Surveys conducted between 1997 and 1999 led scientists to believe that the minimum number left in the Yangtze could be as low as 13 individuals (Zhang et al., 2003).

The last authenticated Yangtze river dolphin records were of a stranded pregnant female found in 2001, and a live animal photographed in 2002 (Turvey et al., 2007). In 2003, a report published by the Chinese Institute of Hydrobiology concluded that the population is probably declining by about 10% per year, suggesting that extinction would occur within a decade (Zhang et al., 2003). During November and December 2006, an international research team, including biologists from NOAA, conducted an intensive six-week multi-vessel visual and acoustic survey covering the entire historical range of the Yangtze river dolphin in the main Yangtze channel between Yichang and Shanghai (1,669 km). By the end of the expedition, the team failed to find any evidence that the species survives, and concluded that the Yangtze river dolphin may now be extinct (Turvey et al., 2007).

Threats The primary threat is bycatch in local fisheries, which use rolling hooks, nets (gillnets and fyke nets), and electro-fishing (Zhou and Wang, 1994; Zhou et al., 1998). Rolling hooks and other fishing gear caused at least half of all known dolphin deaths in the 1970s and 1980s. Electro-fishing accounted for 40% of dolphin deaths recorded during the 1990s (Lin et al., 1985; Chen and Hua, 1989; Zhou and Li, 1989; Zhou and Wang, 1994; Zhou et al., 1998; Zhang et al., 2003). Other threats to the Yangtze river dolphin include (K. Wang et al., 2006b) pollution river development projects vessel collision underwater explosions used to deepen or widen navigation channels or used for illegal fishing are another cause of dolphin mortality.

Zhou and Li (1989) once reported that explosions caused 19.4% of deaths during illegal fishing operations (using explosives) in the lower reaches of the river between 1979 and 1981. The increasing rate of water project development, including construction of dams and floodgates in the middle and lower reaches of the Yangtze, has resulted in blockages between the river and the lakes. The dams interrupted the movements of the Yangtze river dolphins upstream of the dams, and eliminated their access to tributaries and appended lakes (Chen and Hua, 1989; Liu et al., 2000). These dams also caused a notable decline in fish resources (Zhou and Li, 1989). The world's largest dam, the Three Gorges Dam, has been inserted in the middle of a hot spot of bio-diversity in south-central China, which affected the habitats of the Yangtze river dolphin (Chen et al., 1997 in K. Wang et al., 2006b; Zhou, 1991).

Conservation Efforts Five natural reserves have been established along the middle and lower reaches of the Yangtze River since 1986 for the protection of the Yangtze river dolphin, and another rare cetacean species, the Yangtze finless porpoise (Wang et al., 2006). However, these reserves do not prevent the incidental death of these species (D. Wang et al., 2006; K. Wang et al., 2006b). In addition to these natural reserves, two semi-natural reserves were established for the purpose of housing Yangtze river dolphins under human management (Baiji Research Group, 1989; Zhou, 1989). However, neither semi-natural reserve has ever been used for captive propagation of the Yangtze river dolphins. In 1980, a male Yangtze river dolphin was rescued from fishing gear and rehabilitated in Baiji Dolphinarium at the Institute of Hydrobiology of Chinese Academy of Science in Wuhan (Gui and Wang, 2005; Chen and Liu, 1989).

This dolphin died from old age in 2002 after more than 22 years in captivity (K. Wang et al., 2006b). Regulatory Overview In response to the dramatic and rapid decline of the Yangtze river dolphin and other wildlife species between 1985 and 1987, the Chinese Government issued the "Circular for the Protection of Precious and Rare Wildlife" and the "Urgent Circular Banning Hunt, Trade, and Smuggling of Precious and Rare Animals," making the protection of these species a law (Zhou and Zhang, 1991). Subsequently, the Yangtze river dolphin was designated as one of the "First Category of National Key Protected Wildlife Species" in China (K. Wang et al., 2006b). In the United States, all marine mammals, including Yangtze river dolphins, are protected under the Marine Mammal Protection Act (MMPA), as amended. In addition, this species is also listed as endangered species under the Endangered Species Act of 1973. Taxonomy

Question: The 'Baiji' that became extinct in 2006, was a species of which mammal?
Answer: DOLPHIN